Universal test fixtures for automatic testing equipment are commonly employed to removably retain an electronic circuit device in electrical communication with automatic testing equipment. The testing equipment is operative to ascertain whether the electronic circuit device conforms to a predetermined standard of quality whereby functional devices may be readily identified and separated from defective ones.
The test fixtures usually include a regular array of upstanding signal contacts. The geometry defined by the electrical terminals of the electronic circuit device to be tested and the geometry defined by the regular array of upstanding signal contacts of the test fixture, however, are often such that one or more of the electrical terminals of the circuit device are out of coaxial alignment with corresponding ones of the upstanding signal contacts of the test fixture. In such situations, an adaptor is provided for electrically connecting the circuit device to the test head.
One known adaptor includes an array of signal contacts aligned with the electrical terminals of the electronic circuit device to be tested that are individually hand-wired and soldered to preselected ones of an array of signal contacts having a geometry that corresponds to the geometry of the test fixture. However, such hand-wired adaptors are disadvantageous, among other things, due to the considerable time and labor costs involved in hand-wiring the adaptors, and due to the possibility of erroneous results produced by a failure of one or more of the soldered electrical connections.
It is also known to employ an adaptor having an upper plate having apertures provided therethrough in alignment with the electrical terminals of an electronic circuit device to be tested, a lower plate having apertures provided therethrough corresponding to the regular array of signal contacts of the test fixture, and a plurality of flexible probes manually inserted between the plates such that the heads of the flexible probes define an array of contacts in alignment with the electrical terminals of the electronic circuit device to be tested and the tails of the flexible probes define a second array of signal contacts in alignment with the regular array of upstanding signal contacts on the test fixture. This type of adaptor is disadvantageous, among other things, due to the comparatively high cost of flexible probes. Moreover, the tails of corresponding ones of the flexible probes are received in random ones of the apertures of the lower plate which necessitates that a particular adaptor configuration be "learned" by the automatic testing equipment on a known "good" device prior to testing for defective devices.